File:Separase-Is-Required-for-Homolog-and-Sister-Disjunction-during-Drosophila-melanogaster-Male-Meiosis-pgen.1005996.s019.ogv

English: Normal sister kinetochore biorientation followed by segregation failure during meiosis II after THR depletion. Time-lapse analysis of progression through the second meiotic division in spermatocytes expressing cid-EGFP and His2Av-mRFP. Moreover, spermatocyte-specific THR depletion was induced by transgenic RNAi (thr-RNAi). During interkinesis before the onset of meiosis II, sister centromeres are not resolved and appear as a single Cid-EGFP dot. After normal sister kinetochore biorientation in the metaphase II spindle, sister centromeres are stretched apart along the spindle axis. However, sister centromere segregation to opposite poles during exit from meiosis II fails and each pair of sister centromeres coalesces again into a single dot on the bridged chromatin mass present after meiosis II. A poorly visible fine chromatin bridge between two homologs is retracted at onset of the second meiotic division, and therefore one Cid-EGFP dot joins the other dots in the upper cell. Precise genotype description is given in S1 Table. Image stacks with 15 focal planes spaced by 1 μm were acquired with a time interval of 1 min. Scale bar = 5 μm.